Air-dried clay can be fully waterproofed by using either epoxy resin or varnish.
If you just need your clay to be a bit more water-resistant, but not fully waterproof, you could also use paint or white glue such as Mod Podge.
1. Use Epoxy Resin
Jessmatutorials recommends 3 types of epoxy resin to use on clay; Ice Resin 2 part epoxy, Lisa Pavelka Magic Gloss UV resin and Ultradome UV resin.
They all achieve the same result and will waterproof your clay, to use epoxy resin on your air-dried clay follow these steps:
- Mix the resin with its hardener.
- Pour the resin over your clay.
- Use a brush to paint resin over any areas that may otherwise be missed.
- Leave it to dry – it should feel dry to touch within 24 hours but we recommend leaving it for 72 hours to allow it to completely dry.
2. Use Varnish
Clear polyurethane varnish is ideal for waterproofing clay, however pretty much any type of varnish will do the job effectively.
To waterproof your air-dried clay using varnish follow these steps:
- Apply a thin even coat of varnish, either by rubbing or spraying it on.
- Leave 4-6 hours to dry.
- Apply second and third coats if required.
3. Other Methods
Varnish and epoxy resin are the only ways to fully waterproof your air-dried clay. However if just need your clay to be a bit more water-resistant, for example, if you aren’t going to be leaving it outside or submerging it, then there are many other ways that this can be achieved:
- Paint – acrylic paints are not waterproof however they have a reasonable level of water- resistance. Painting your clay with acrylic paints will help protect it.
- Mod Podge – be aware that over time if exposed to the sun mod podge can turn yellow which can ruin the look of the clay.
While neither of these methods will make your clay completely waterproof they will give it a good level of water resistance which is enough for most use cases.